Sunday, August 23, 2009

The Lemon-Powered Clock

The first time I powered a clock using the electricity generated from a lemon, I did it using two pieces of fruit, pennies, zinc coated paperclips, and copper wire. I rigged everything up according the instructions. Then we waited, eight kids and three parents staring at the tiny LED screen. I knew it should have happened instantly so I wiggled things around. Just as I was about to give up, one of the kids said, “It’s working!” We’d created an electrical circuit!

I now have a couple of nifty kits specifically designed to extract electricity from a single piece of fruit, but each time we bring that small clock to life, I get that same sense of excitement I did the first time. It works!

And the kids get it. Last year, my Pre-K children spontaneously applauded when the clock lit up. They knew they were watching something very cool. Electricity from a lemon! Our 2 and 3-year-olds wouldn’t appreciate how exciting it is, so they have to wait for next year. This is something we save for the 4-year-olds who know enough to doubt that we can get electricity out of a lemon, which allows them to be appropriately impressed when we do.

After this amazing experiment I get out our set of Snap Circuits and build a simple circuit to power a light bulb. Then we turn on a small motor that causes a pinwheel to soar over our heads. The children want to try it themselves so badly, but they have to wait until it’s time for “stations” to get their hands on the Snap Circuit sets.

I then divert them into turning the classroom lights off and on. As we do it, I talk about how they are “breaking” or “reconnecting” circuits each time they flick the switch. I point out the streetlights and remind them of the stoplights and the lights in their homes. We talk about how we make electricity work for us by routing it into circles.

We then spend the rest of our day looking for “circles” in the world, both physical and metaphoric. We move on from geometric circles to more abstract circles, like bus routes, daily routines, and seasons. We wait for the second hand on our analogue clock to complete a one-minute circuit. We talk about hours, days, weeks, months, and years. We act out the circle of seed, sprout, leaves, flower, fruit, and back to seed again from whence we start all over. We notice that everything that lives does so in a circle we call a life cycle.

For weeks thereafter, kids always have new insights about circles.

This past year Jane arrived in class the day after our experiment and asked excitedly, “Did you know the Earth revolves around the Sun?”

Mikey pointed out that the wheels on his mom’s car were circles.

Esme wanted me to know that the letter “O” is a circle “and so is zero.”

Elliott T. informed us that many of the shapes we were calling circles were actually not circles, like the trip he took each day from his house to school, which was really a “long, skinny oval.”

When I read Eric Carle’s book The Tiny Seed, Nia’s hand shot up, “The whole story is a circle!”

Keira painted a circle inside of a circle inside of a circle.

Malcolm and Jarin raced their cars around a “circle” racetrack they created in the block area.

Ava made play dough donut and bagel circles.

Elliot O. wanted to know why we call it “Circle Time” if we don’t sit in a circle.

Each of these insights might seem small, maybe not even worth mentioning, but they’re vitally important to understanding our physical world. I like to imagine Stephen Hawking as a preschooler, tracing circles in the sandbox, beginning the chain of insightful connections that have lead to a deeper understanding of the orbiting of planets, the Big Bang, black holes, and light cones, none of which would be at all comprehensible without our preschooler’s understanding of the circle.

But circles are not just key to understanding the physical world. They are essential to comprehending the metaphysical as well. As another great scientist realized:

Our task must be to free ourselves by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty. –Albert Einstein

That’s why each year, over and over, we make the lemon-powered clock. It makes us cheer and makes us think big thoughts.

1 comment:

This is a great post!! I love this!! For awhile I taught a bunch of grown men about cycles and amplitude, watts and much more. It's very technical stuff but once you wrap your brain around it, it totally helps to understand how lots of stuff works. Too cool. Though now that some years have passed, I'll probably need a refresher course on the subject so I can't wait to see your experiment live.

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About Teacher Tom

I am a preschool teacher, blogger, speaker, artist and the author of Teacher Tom's First Book (teachertomsfirstbook.com)
For the past 15 years, I've taught preschool at the Woodland Park Cooperative School. The children come to us as 2-year-olds in diapers and leave as "sophisticated" 5-year-olds ready for kindergarten.
The cooperative school model allows me to work very closely with families in a true community setting.
I intend to teach at Woodland Park for the rest of my life. I love the kids and I love the families. It's an incredibly rewarding job.